A retrospective cohort study of approximately 12,000 women with cosmetic augmentation mammoplasty is planned. The women will be assembled from a number of different plastic surgery practices in geographically dispersed areas. Attempts will be made to achieve an average of 10 years of follow-up and to have a sufficient number of women with different types of implants, particularly the polyurethane foam coated types. Medical records will be abstracted for information on patients characteristics and details regarding the types of implants received. The women will be traced to the present time through various mechanisms, and will then be sent a questionnaire to obtain information on subsequent adverse outcomes and risk factors for selected conditions. To determine whether these women experience unusual risks of cancer, comparisons will be made with available cancer incidence statistics. In addition, an internal comparison group of approximately 4,000 patients undergoing other types of plastic surgery will be assembled, traced and questioned in a manner similar to the implant patients. This comparison group will enable evaluation of whether characteristics related to the seeking of plastic surgery have an impact on subsequent disease risk. This internal comparison group will also serve as a base for developing incidence rates of diseases for which population statistics are not available, e.g., the immune conditions that have been linked anecdotally to breast implants.